This invention relates to a pressure swing adsorption apparatus for generating enriched product gas in which the timing of the valves controlling the flow of gas to the adsorber beds and a boost compressor is chosen to maximize system efficiency.
The use of concentrators of the pressure swing adsorber type to produce an enriched product gas is well known. Pressurized air is cyclically delivered to a plurality of beds of molecular sieve material, and certain components of the air become adsorbed by the sieve while the chosen component passes through. The beds are sequentially vented to atmosphere and purged with product gas to discharge the adsorbed components from the molecular sieve, and in this manner, a continuous flow of enriched product gas can be generated.
In certain situations, the required pressure of the product gas is higher than the output pressure from the adsorber and a pressure booster may be used to increase the pressure of the product gas in order to meet system requirements. Booster compressors themselves are old in the art and may take several forms. Some are electrically driven but in certain situations a pneumatically driven booster provides advantages. The pneumatic booster may be driven in sync with the beds of the pressure swing adsorber and such a system is shown in the U.S. Pat. No. to Hradek, 5,071,453 assigned to the assignee of the instant invention. The pressure swing adsorber and booster combination may be used in an aircraft environment where space and weight restrictions are always a factor. The instant invention maximizes system efficiency and thus minimizes weight and space requirements for the system by timing the valves which control the flow of gasses to the sieve beds and the booster to recover energy from the system which is otherwise wasted by being vented to atmosphere.